How Much Protein Do You Actually Need on a Cut?

Most people eating in a deficit under-eat protein, under-eat it consistently, and then blame the cut for the muscle loss that follows. The research on this is clear enough that there is no good reason to guess. Here is what the evidence actually says, how to personalise the number for your situation, and what goes wrong when people get it wrong.

The baseline number and why it is higher than you think

A 2011 meta-analysis by Phillips and Van Loon put the muscle-preserving minimum at around 1.6 g per kg of bodyweight per day for resistance-trained individuals in energy balance. When you drop calories, that floor rises. A 2014 Helms et al. review of natural bodybuilders recommended 2.3 to 3.1 g per kg of lean body mass during a cut, with the higher end applying to leaner athletes who have less fat to lose and therefore more muscle at risk. For a practical starting point, use 2.2 to 2.6 g per kg of your total bodyweight if you are above 20 percent body fat, and shift to 2.6 to 3.1 g per kg of lean mass if you are already lean, say under 15 percent for men or under 23 percent for women.

A 90 kg person at 22 percent body fat (roughly 70 kg lean mass) lands at about 185 to 215 g of protein per day. That is not a small number. For most people eating 1,800 to 2,200 calories on a cut, protein ends up taking 35 to 45 percent of total intake.

Why the requirement goes up when you eat less

Two mechanisms drive this. First, muscle protein synthesis needs adequate amino acid availability to run, and a calorie deficit blunts the anabolic signal from training. Higher protein partially compensates for that. Second, your body becomes more willing to oxidise muscle tissue for fuel when carbohydrate and fat intake falls. Protein acts as a buffer by keeping the amino acid pool full, making it less convenient for your body to raid skeletal muscle. There is also a thermic effect worth mentioning: protein costs around 25 to 30 percent of its own calories to digest, compared with 6 to 8 percent for carbohydrate and 2 to 3 percent for fat. On a 200 g protein intake, that is roughly 200 to 240 calories burned in digestion alone.

Spreading it across the day

Total daily intake matters most, but distribution is a secondary lever with real returns. Research by Areta et al. (2013) showed that spreading 80 g of protein across eight small doses was inferior to four doses of 20 g for muscle protein synthesis, and a single large dose did not outperform either. A practical target is four meals with 40 to 55 g of protein each. Pre-sleep protein, specifically around 40 g of casein-rich food like cottage cheese or Greek yoghurt, consistently shows benefits for overnight muscle protein synthesis in studies from Maastricht University. If you train fasted in the morning, get a protein-containing meal within 60 to 90 minutes of finishing.

What happens when people get this wrong

The two failure modes are opposite. Under-eating protein on a cut produces disproportionate lean mass loss, a slower metabolism, and worse hunger control. Protein is the most satiating macronutrient gram for gram, so falling short usually means more snacking on lower-satiety foods and a deficit that collapses mid-week. Over-eating protein is less dangerous but does carry an opportunity cost. Pushing above 3.5 g per kg of bodyweight adds expense, digestive load, and crowding out of carbohydrates that support training performance. The sweet spot is real. Hitting 2.4 to 2.8 g per kg of bodyweight for most recreational lifters covers the evidence and leaves room for enough carbohydrate to keep sessions productive.

Adjusting as the cut progresses

Your protein target should not be static. As you lose weight, recalculate every four to six weeks. If you started at 95 kg and are now 87 kg, your protein floor has dropped by roughly 17 to 19 g per day. More importantly, as you get leaner, the risk to muscle increases, so the per-kilogram target should trend upward even as the absolute number comes down. Keep training volume and intensity as high as recoverable. Protein cannot fully compensate for a programme that drops the stimulus for muscle retention.

Getting the protein number right is one calculation. Staying consistent with it over a 12 to 16 week cut, adjusting it every month, and catching the weeks where adherence slips is a different problem entirely. AskCoach reads your logged macros each day and flags when your protein average is trending below your target before the deficit does damage, no spreadsheet required.